TO: Dr. Clifford K. Beck
FROM: A. C. Menius, Jr. and Raymond L. Murray
SUBJECT: Graphite and Lead Requirements
CC: L. H. Robinson, Newton Underwood, and A. W. Waltner

GRAPHITE:

The requirements on reflector and thermal column graphite were given to the
Atomic Energy Commission in a letter of May 23 as follows: (Assume the graphite density is 1.61x62.4 lb/ft³ = 100 lb.ft³)

Number	Size (in.)	Volume per block (in.³/ft.³)	Weight per block (lb.)	Total Weight (lb.)
485	4 3/8 x 4 3/16 x 44	806.1/0.466	46.6	22,600
260	4 3/8 x 4 3/16 x 40	732.8/0.424	42.4	11,020
50	4 x 4 x 12	192.0/0.111	11.1	550
34,170 or 17 tons

The basic design calls for a 5' x 5' x 5' reflector and a 5' x 5' x 5' thermal
column (neglecting the core and the lead shielding.). The volume is thus only
250 ft.³, the weight 25,000 lb. or 12.5 tons. The excess of 4.5 tons will take
care of machining and breakage. An estimate of needs can be made to include only
machining losses.

Assuming that the units of construction are 4" x 4" x 41" (cut from the 44"
pieces), and 4"x 4" x 19" (two cut from the 41" pieces), that each 5' x 5' x 5'
cube is formed by 15 courses, each consisting of 15 "longs" and 15 "shorts", then
225 of the 40" and 450 of the 44" are needed. The specifications to Oak Ridge
incorporate 35 extras of each of the 40" and 44" and 50 twelve inch pieces.

LEAD:

It is assumed that bricks 2" x 4" x 8" are used. Each has a volume of 1/27 ft.³,
with a specific gravity of 11.3. The specific weight is 705 lb./ft.³. Each brick
weighs 1/27 x 705 = 26.1 lb. The agreed locations and dimensions of lead are:

Top and two sides	2"
Back	4"
Thermal column	8"

The total thickness is thus 18". With an area of 5' x 5', this gives 37.5 ft.³,
or 705 x 37.5 = 26,400 lb.; or 13.2 tons. Considering the saving at corners and
unavailable space at the top, 13 tons is adequate.